Stitch-forming mechanism for sewing-machines



G. S GATCHELL. STITCH FORMING MECHANISM FOR SEWING MACHINES. 1,365,239.

APPLICATION FILED NOV-2h I9I8.

- Patented Jan. 11, 1921.

3 SHEETS-SHEET I.

lTVI/E/I/ T0)? G. S. GATCHELL.

STITCH FGHMING MECHANISM FOR SEWlNG MACHINES, APPUCATION FILED H0121. 1918.

1 3 5 239 Patented Jan. 11, 1921.

3 SHEETS-SHEET 2.

INVENTOR BY v W TTORNEY WITNESSES G. S. GATCHELL.

STITCH FORMING MECHANISM FOR SEWING'MACHINES.

Patented Jan. 11,1921.

3 SHEETSSHEET 3.

APPLICATION FILED NOV. 2!, 918.

ATTORNEY UNITED STATES PATENT OFFICE.

GEORGE S. GATCI-IELL, EOSELL-E PARK, NEW JERSEY, ASSIGNOR TO THE SINGER MAIQ'UFAOTURING COMPANY, A CORPORATION OF NEW JERSEY.

STITCH-FORMING MECHANISM FOR SEWING-MACHINES.

Specification of Letters Patent. Pate t d J 11 1921 Original application filed August 10, 1917, Serial No. 185,446. Divided and this application filed November 21, 1,918.

T 0 all w hom it may con 0cm a citizen of the United States, residing at Roselle Park, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Stitch- Forming Mechanisms for Sewing-Machines, of which the following is a specification, reference being had therein to the accompanying drawings. 7 I

This invention relates to improvements in the stitch-forming mechanism of multipleneedle single-loopcr sewing machines of the type disclosed in the United States patent to George E. Molyneux and George S. Gratchell, No. 1,266,036 ofMay 14, 1918, and has for an object to provide means for preventing the crowding together of the needleloops on the looper and for maintainingthe needle-loops evenly spaced apart on the looper and in positions such that each needle will invariably pass down at the proper side of its respective previously formed loop,

without catching the thread of or entering said loop.

A further object of the invention is to improve the relative timing of the passage of the needle points by the respective previously formed needle-loops, whereby suchpassage will occur when the looper-blade occupies a favorable angular position relativelyto the direction of reciprocation of the needles.

In attaining the above and other ob ects,

as will hereinafter more fully appear, the

machine is fitted with loop-detainers,,one of which holds back on the looper-blade the first loop entered by the looper, so that said loop cannot possibly slip forwardly and into the path of its corresponding needle during the loop-shedding strokeof thelooper. The remaining loop-detainers hold their respective loops forwardly on the looper-blade and prevent said loops from. being draggedback into the paths of adjacent needlesby the retracting looper. The needles of the machine have their eyes arranged at progressively lower elevations beginning with the first needle-eye passed by the advancing looper,

while the needle points are disposed in a common plane at right angles to thedirection of travel of the needles, sothat the needle points enter the work simultaneously and pass their respective previously formed Serial N0. 263,451.

loops on the looper substantially simulta neously. I

In the accompanying drawings, Figure 1 13 a side elevation partly in section of a machine embodying the invention. F ig. 2 is a plan view of the front end of the worksupporting arm. Fig. 3Vis a front elevation of the parts adjacentthe stitching point of the machine on an enlarged scale. Figs. 4 and 5 are perspective views of the mechanism at the under side of the throat-plate showin the cooperation of the looper and needle loop-detainers. Fig. 6 is a top plan view illustrating the cooperative relation of the needles, looper, needle-loops, and needle,

loop detainers, Fig. 7 is a verticallongitw dinal section on the line 77 of Fig. 6. Fig. 8 is a similar view on the line 8-8, of ofFig. 6, andFig. 9 is a perspective view of a connection in the looper-operating- 5 which is formed with two angularly arranged flat sides 6, 7, Fig. 3, and a curved upper side 8, whereby said work-arm issubstantially secto1-shaped in cross-section. Secured to the front or free end of the workarm casting is the throat-plate 9 whose opposite lateral edges are grooved at 10 to slidably receive and. support the end cap 11 which is sector-shaped at its rearward end to conform to the cross-sectional shape of the work-arm. The under surface of the end cap tapers upwardly and the sides thereof taper forwardly toward the free endof the throat-plate, as shown in Figs. 1 and 2, to facilitatethe advance of the tubular work about the work-arm and toward the stitchupper strapped end of which embraces a ball-ended crank-pin carried by the crank-arm 16 at the rear end of the needleactuating rock-shaft 17 which is journaled within the bracket-arm 3 and, at its forward end, carries a crank-arm 18 connected to the reciprocating needlcbar 19 by means of the link 20. Secured to the lower end of the needle-bar 19 is the needle-clamp-block 21 which, in the present instance, is socketed to receive four needles a, 02 n and n arranged in a vertical plane transversely of the work-arm Mounted within the end cap 11, in cooperative relation with the needles, isthe thread-carrying looper 22; the upper edge of the blade of which is curved concentrically with the curved upper side of the work-arm, Fig. 3, while the lower edge 23 of said blade is but slightly curved or may even be substantially straight throughout a portion of its length. The slotted shank of the looper is secured to the looper-support 24 by a screw 25 permitting adjustment of the looper-blade toward and from the stitching plane. The loopersupport is clamped to the front end of the oscillating and endwise movable looper-shaft 26 which is journaled within and lengthwise of the work-arm 5 as closely as practicable to the apex of the angle formed by the flat sides 6 and 7 there of, Fig. 3, said angle being large enough to accommodate the necessary loop-seizing and shedding strokes of the looper.

It will be seen by referring to Fig. 3 that the needle-eyes are arranged on an incline; being placed at progressively lower elevations beginning with the needle 71. to coinpensate for the upward movement of the needles as the looper-beak advances across the space between said needles; the purpose being to insure the passage of the looperbeak at the correct distance above each needle-eye to insure seizure of the respective needle-loop. It will be further seen that the needle points are arranged substantially in a common plane parallel to the plane of the throat-plate; the purpose being to insure that the previously formed needle-loops on the looper will be passed substantially simultaneously by their respective needles at the time the lower edge 23 of the looper-blade occupies a substantially horizontal or otherwise favorable angular position relatively to the throat-plate.

The looper-shaft 26 carries at its rearward end a crank-arm 2'? having a ball-crank-pin 28 which is embraced by the lower strapped end of a link 29 the upper strapped end of which embraces a ball-eccentric on the mainshaft 12 which imparts loop-seizing and shedding movements to the looper. The hub of the crank-arm 27 is formed with a rearward extension carrying a ball-ended pin 30 disposed concentrically with the axis of the looper-shaft and embraced by. the socketed end of a link 31 whose opposite end is connected to the depending arm 32 of a rock-lever fulcrumed to oscillate upon and independently of the cross-shaft 33 journaled in the standard 2. The upwardly extending arm 34 of said rock-lever is slotted at 35 to receive an adjustable pin 36which, through the pitman 37, connects said lever with the eccentric 38 carried bv the mainshaft; said eccentric servin to impart sidewide or needle-avoiding movements to the looper.

To insure against abnormal displacement of the needle-loops on the looper the machine is equipped with loop-detainers comprising, preferably, three hooked fingers 39 for cooperation with the loops of the needles 71?, n and n and an additional oppositely hooked finger 40 for cooperation with the loop of the needle n. The detainers 39 are formed at the end of a plate 41, the slotted shank of which is entered by a screw 42 securing the shank of said plate within a groove 43 at the under side of the throatplate, thereby permitting adjustment of said fingers lengthwise of the throat-plate and facilitating accurate positioning of said fingers relatively to the needles and looper.

The tip ends of the detainers 39 are curved or inclined opposite to the direction of retraction of the looper and are positioned between the needle-paths and above the looperpath each at that side of its respective needle which faces the direction of retraction of the looper so as to engage the upper limbs of the respective previously formed needle-loops extending between the last stitch and the curved upper edge of the looper-blade, as shown in Figs. 6 and 8 and prevent the retracting looper from dragging said loops back into the paths of their respective next adjacent needles. .In practice, it is found that there is a tendency for the previously formed loop of the needle n to slip toward the point of the looper and into the path of said needle. To avoid this difiiculty, the looper-blade may be notched to provide a shoulder 44 adapted to engage the loop of said needle n during the first part of the retracting stroke of the looper, as shown in Fig. 4, and drag said loop backwardly a slight distance past said finger 40, the looper at the same time also moving sidewise under said finger, whereupon the loop slips over the shoulder 44 and is detained at one side of the path of the needle n by said finger 40, as shown in Figs. 5 and 7. The tip end of the finger 40 is preferably curved or directed slightly toward the direction of retraction of the looper-blade and is made separately from the detainers 39 being, in the present instance, secured to the plate 41 by a screw 45 which permits adjustment of the finger 40 about said screw as a pivot.

The invention is not to be understood as limited to the exact details of construction shown and described as it will be apparent to those skilled in the art that it is susceptible of embodiment in many other forms within the scope of the invention.

Having thus set forth the nature of the invention, what I claim herein is 1. In a sewing machine, in combination, a plurality of reciprocating needles, a single thread-carrying looper cooperating therewith to form stitches, and a plurality of stationar loopdetainers for maintaining each. needle-loop at that side of its respective needle-path which faces the direction of retraction of the looper.

2. In a sewing machine, in combination, feeding mechanism, a plurality of reciprocating needles set in a plane crossing the line of feed,'a single thread-carrying looper cooperating therewith to form stitches, and a plurality of stationary loop-detaining fingers constructed and arranged to engage the respective needle-loops on the retracting looper and hold said loops properly spaced and each at that side of its respective needlepath which faces the direction of retraction of the looper.

In a sewing machine, in combination, feeding mechanism, a plurality of reciprocating needles set in a plane crossing the line of feed, a single thread-carrying looper cooperating therewith to form stitches, and a plurality of stationary loop-detaining fingers extending in the direction of feed and between the needle-paths and each at that side of its respective needle-path which faces the direction of retraction of the looper and adapte to engage the respective needleloops on the retracting looper and hold said loops properly spaced and each at the side of its respective needle-path.

at. In a sewing machine, in combination, feeding mechanism, a plurality of reciprocating needles set in a plane crossing the line of feed, a single thread-carrying looper with means for advancing it in rear of the needles, then giving it a sidewise movement in opposition to the direction of feed and a retract ing movement in front of the needles, a plurality of loop-detaining fingers extending in the direction of feed and between the needlepaths and each at that side of its respective needle-path which faces the direction of retraction of the looper, the looper operating in its sidewise movement to carry the upper limbs of the needle-loops into engagement with the respective loop-detainers, whereby said detainers hold the needle-loops in properly spaced relation on the looper-blade.

5. In a sewing machine, in combination, a plurality of reciprocating needles set in a plane cross the line of feed, an oscillating looper cooperating therewith to form stitches, a loop-detainer acting to hold one of the needle-loops back on the blade of the retracting looper and another loop detainer acting to hold another of theneedleloops forward on the looper-blade,thereby overcoming the natural tendency of said loops to crowd together on said looper-blade.

6. In a sewing machine, in combination, a plurality of needles, a-single looper cooperating therewith to form stitches, a pair of loop-detainers disposed one on each side of a given one of said needles, means for producing relative movement between said needles, looper and detainers to cause the positioning of both detainers between a pair of adjacent needle-loops, whereby said loops are held apart and on opposite sides of the path of said given one of said needles.

7. In a sewing machine, in combination, a plurality of needles, a threaded looper 00- operating therewith to form stitches and formed at its forward end with a loop-seiz;

ing beak and at its rearward end with a loop-engaging shoulder adapted to engage the first needle-loop entered by the looper and drag said loop rearwardly a short distance during the first part of the retracting stroke of said looper, a loop-detainer adapted to engage said loop after it slips over said shoulder and prevent it from sliding forwardly on the looper-blade into the path of its corresponding descending needle, and additional loop-detaining means adapted to engage the adjacent needle loop and prevent it from being dragged back by the retracting looper into the path of said descending needle.

8. A sewing machine comprising, in combination, a plurality of needles set in a plane crossing the line of feed, a thread-carrying looper cooperating therewith to form stitches and at its rearward end having a loop-engaging shoulder fOr catching and dragging back the first loop entered by the looper, means for imparting loop-seizing and loopshedding movements to said looper, a loopdetainer having a loop-engaging point inclined in the direction of loop-shedding movement of the looper to hold back on the looper-blade the loop dragged back by said shoulder after said loop slips forwardly over the latter, and a second loop-detainer having a point inclined in the direction of advance of the looper to hold the adjacent needleloop forwardly on the loopenblade and prevent said loop beingdragged back into the path of the next adjacent needle during the retraction of said looper.

9. A sewing machine comprising, in combination, a plurality of needles, a threaded looper cooperating therewith to form stitches and formed at its forward end with a loop-seizing beak and at its earward end with a loop-engaging shoulder adapted to engage the first needle-loop entered by the looper and drag said loop rearwardly a short distance during the first part of the retracting stroke of said looper, a loop-detainer having a point curved toward the direction of retraction of the looper and adapted to engage said loop after it slips over said shoulder and prevent it from sliding forwardly on the looper-blade into the path of its corresponding descending needle, and a second loop-detainer adapted to engage the adjacent needle-loop and prevent it from being dragged back by the retracting looper into the path of said descending needle.

10. A. chain-stitch sewing machine comprising, a plurality of eyed and pointed needles, a single looper cooperating therewith to term stitches, loop-detaining means cooperating with said looper, the eyes of said needles being placed at progressively lower elevations beginning with the first needle passed by the advancing looper, and the points in said needles being disposed at substantially the same elevation, whereby the advancing looper-beak will pass each needle at the proper distance above its eye and whereby the needle points will pass the previously formed and detained needle-loops substantially simultaneously.

11. A chain-stitch sewing machine comprising, a plurality of eyed and pointed needles, and a single looper cooperating therewith to form stitches, theeyes of said needles being placed at progressively lower elevations beginning with the first needle passed by the advancing looper, and the points in said needles being disposed at substantially the same elevation, whereby the advancing looper-beak will pass each needle at the proper distance above its eye and whereby the needlepoints will all pass the retracting looper-blade substantially simultaneously.

In testimony whereof, I have signed my name to this specification.

GEORGE S. GATGHELL. 

